Genetic and biophysical methods will be employed to elucidate the molecular events that result in genetic recombination. The roles of DNA branch migration and the biochemical and genetic consequences of the presence of base-pair mismatches will be investigated using bacteriophage lambda recombination as a model system. Kinetic analysis and biochemical confirmation of the intermediate steps in bacterial DNA uptake will be carried out in order to identify the substrate of the subsequent recombination events that occur in bacterial transformation. BIBLIOGRAPHIC REFERENCES: White, R. L. and Fox, M. S. Genetic Heterozygosity in Unreplicated Bacteriophage Lambda Recombinants. Genetics 81: 33-50 (1975). White, R. L. and Fox, M. S. Genetic Consequences of Transfection with Heteroduplex Bacteriophage Lambda DNA. Molec. Gen. Genet. 141: 163-171 (1975).